The invention relates to a process for correcting signal distortions which occur in frequency-modulated data transmission when a rectangular binary signal is derived from a faulty, demodulated signal. In this process a correcting signal is formed using a corrected demodulated signal and the rectangular binary signal and thus the signal distortions are counteracted.
The telegraphy transmission devices operated with frequency modulations, frequency drifts on the transmission path cause distortions of the telegraphy signals at the receiver. As is known, such distortions may be corrected if a correcting signal is formed with the aid of the demodulated signal. Using such a correcting signal, it is possible either to change the d.c. voltage component of the demodulated signal or to carry out a frequency conversion of the signal transmitted across the transmission path in such manner that a substantially fault-free, demodulated signal is emitted. These known processes only operate satisfactorily if the amplitude range of the demodulated signal is equal to a given theoretical value for the duration of individual telegraphy signals.
An object of the invention, therefore, is to provide a process for correcting signal distortions which provides a satisfactory correction even when the amplitude range of the demodulated signal is smaller than the afore-mentioned given theoretical value for the duration of individual pulses of the rectangular binary signal.